Switch-mode power supplies (SMPS) are power management components in modern electronic devices. They provide, among other things, power efficient and galvanically isolated power to multiple loads. In order to achieve high power processing efficiency and/or galvanic isolation, conventionally one or more magnetically coupled elements, semiconductor switches and associated gate driver circuits are required.
The magnetically coupled elements often suffer from non-trivial leakage inductance phenomena, which necessitate the need for affordable voltage snubber circuits in order to control the semiconductor switch peak drain-to-source voltages. As a result of the price sensitive nature of SMPS, the snubber circuits are typically limited to the cost-effective passive and power lossy resistor-capacitor-diode (RCD) configurations.
In systems sensitive to power losses and heat generation, the dissipation in lossy components in the form of heat is unsuitable. Recycling of energy within the system provides an opportunity for system form-factor reduction and power efficiency improvement.
Clamping the maximum drain source voltage of switching power transistors allows for increased device reliability and use of power transistors with improved figure-of-merit (FOM). The improved FOM enables the SMPS to operate at higher switching frequency while maintaining high power processing efficiency. Furthermore, it allows for a reduction of the SMPS reactive component size and cost.
Conventional auxiliary power supplies required to operate the gate drivers are not well suited for modern multiple-switch high voltage floating and/or high-side applications, due to their complexity, low power processing efficiency and/or high cost. There remains room for improvement at the system and circuit level.